30 PROCEEDINGS OF THE NATIONAL MUSEUM VOL. 92 
Mebhlis’s gland grouped on each side, the complex about 1.4 to 1.5 
mm. across, the midline of each about midway between margin of 
proglottid and median line of proglottid. Each ovary about 630z 
to 700u in diameter; Mehlis’s gland about 500u long and 350y broad. 
Uterine stems in mature proglottids curve slightly inward; mature 
uteri barely touch at median line, and together occupy about three- 
fifths of width of segment. Cirrus sac about 1 mm. long and 560z 
broad; everted cirrus 700u long and 220y broad. Eggs in the uterus 
are about 75y long. 
Host.—Platysqualus tudes (Cuvier). 
Location.—Spiral valve. 
Type specomen.—U.S.N.M. Helm. Coll. No. 36784. 
Remarks.-—The only other Tetrarhynchidea in which double sets 
of reproductive organs have been described are members of the 
genus Dibothriorhynchus, but the present worm certainly does not 
belong in that genus. Up to the present time all species of tetra- 
rhynchideans having ciliated pits on the bothria have been placed in 
Linton’s genus Otobothrium, but there is a very considerable variation 
in the proportions of the parts of the head and in the armature of the 
proboscides, and it may be that several genera will bave to be recog- 
nized when the adults are known. Otobothrium robustum Chandler, 
1935b, shows distinct affinity with the present species in the robust 
proportions of the head and in the armature of the proboscides, but 
it differs greatly in the distance between the bothria and the contractile 
bulbs and in the area on the proboscis occupied by small hooks. It 
is quite possible that O. robustum may prove to be a Diploétobothrium, 
but it may best be left where it is until the adult is known. 
Genus DASYRHYNCHUS Pintner 
DASYRHYNCHUS INSIGNE (Linton, 1924) 
FIGurReE 3 
A worm obtained from the spiral valve of Carcharias platyodon 
(Poey) is assigned to this species. It agrees very closely with Linton’s 
description of the worm except that in his specimens segments situated 
10 cm. from the head and having a developing uterus are broader 
than long, whereas in my specimen proglottids 9 cm. from the head 
are over twice as long as broad. The contractile bulbs are longer 
relative to the rest of the scolex in my specimen than in Linton’s, 
but the coiling of the proboscis sheaths shows that the middle portion 
of the head is considerably contracted. There are certain features 
of the armature of the proboscis not evident from Linton’s figures; 
these are shown in my fig. 3, a-c, in order to facilitate diagnosis in 
the future. The worm was recorded by Linton (1924) from C. 
milberti and C. commersonii at Woods Hole. 
